Oriented Crystallization of Polyethylene in Compatible Blends with Polyamide 11 |
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Authors: | Akira Kaito Yuko Iwakura Yongjin Li Hiroshi Shimizu |
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Affiliation: | Nanotechnology Research Institute, National Institute of Advanced Industrial Science and Technology , Tsukuba, Ibaraki, Japan |
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Abstract: | The oriented crystallization of polyethylene (PE) in uniaxially oriented films of compatible blends with polyamide 11 (PA11) was studied. The PE sample used was a random copolymer of PE with methacrylic acid (MAA), poly(ethylene-co-methacrylic acid) (PEMAA), with 4wt% MAA units. Oriented films of PA11/PEMAA blends were prepared by uniaxial drawing of the melt-mixed blends. The drawn films with fixed lengths were heat-treated at 120°C for 3min to melt the PE component, followed by cooling the sample to room temperature at a rate of 2°C/min to recrystallize the PE (designated slowly crystallized sample). The PE component crystallized in elongated domains of PEMAA with diameters of 0.5–2 μ m and lengths of 5–10 μ m for the PA11/PEMAA = 80/20 blend, resulting in the oriented crystallization of PE crystals. The crystal b-axis of PE was highly oriented in the direction perpendicular to drawing, while the crystal a-axis was weakly oriented in the drawing direction in the slowly crystallized sample of the PA11/PEMAA = 80/20 blend. The a-axis orientation of PE crystals in the PA11/PEMAA = 80/20 blend contributes to the improvement of mechanical properties in the direction perpendicular to drawing. |
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Keywords: | polymer blend oriented crystallization crystal orientation phase morphology mechanical properties |
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